1. Field of the Invention
The present invention relates to an optical path-changing member that is provided at a terminal of an optical transmission body such as an optical fiber. An optical path-changing member is an optical component for changing a direction of an optical path between an optical fiber and a light input and output end provided at a substrate, thereby optically connecting the optical fiber and the light input and output end.
2. Description of Related Art
In recent years, a method to fix an optical connector assembled to a leading end portion of an optical fiber wired along a substrate on which an optical element such as a light-emitting element such as a surface emission type laser diode (Vertical Cavity Surface Emitting Laser, hereinafter referred to as a VCSEL) or a light-receiving element such as a photodiode (PD), in which light is vertically emitted or incident with respect to the substrate, is mounted, to the substrate so as to be optically connected to the optical element has been widely used.
In this type of optical connector, a structure to change an optical path in order to optically connect the optical fiber and the optical element is provided. As a typical optical connector having this structure, a PT optical connector (standardized by JPCA-PE03-01-06S) which changes an optical axis by 90° in the inside of the connector has been put to practical use.
The PT optical connector is a substrate mounting type optical connector that optically connects a multi-core optical fiber such as a multi-core optical fiber ribbon and an optical element on a flexible wiring substrate, and is beginning to be used in optical interconnection of routers, servers, parallel computers, or the like.
As an optical path-changing member that changes a direction of an optical path of a multi-core optical fiber, there is an optical path-changing member described in Japanese Unexamined Patent Application, First Publication No. 2006-184782. This optical path-changing member has a function to change an optical path of a two-dimensionally arranged multi-core optical fiber and has a structure to prevent occurrence of a large optical path difference by inclining a multi-core optical fiber of an upper stage with respect to a multi-core optical fiber of a lower stage, thereby bringing leading ends of the multi-core optical fibers of the upper and lower stages close to each other. Light emitted from the optical fiber or the optical element is of an external reflection type in which the light is incident on a reflection surface from the outside of an optical path-changing member main body.
As the optical element that is connected to the multi-core optical fiber, an optical module is used. The optical module is an optical component with a multi-channel light-emitting and light-receiving element and a transceiver circuit built therein.
In Japanese Unexamined Patent Application, First Publication No. 2007-121973, as an optical path-changing member, an internal reflection type PT optical connector is disclosed in which light is incident on a reflection surface from the inside by way of an optical path-changing member main body. A lens is formed on the lower surface of the optical path-changing member, and light emitted from a leading end portion of an optical fiber is totally reflected to the circuit board side by a reflection surface and then condensed by the lens, thereby being optically coupled to a light input and output end on the circuit board side. Further, in a case where an optical element on the circuit board side is a light-emitting element, light emitted from the light-emitting element is condensed by the lens and then totally reflected by the reflection surface, thereby being optically coupled to the leading end portion of the optical fiber.
In the above-described optical path-changing members, since the reflection surface has the form of a flat slope, there is a problem in that it is difficult to change an optical path of incident light to an optimum direction. If the reflection surface has the form of a flat slope, there is a case where a shift occurs in a direction of incident light or a case where an optical connection cannot be maintained.